In all the chaos they had to go through, Regulus had almost forgotten about the Slytherin Locket that he had swapped in order to get rid of Voldemort's Horcrux. One day when Kreacher came up to him with that locket and asked about what to do next, he recalled what he had been intending to do before Lord Voldemort himself had shown up to the cave and dragged him away.

That locket contained a fragment of the Dark Lord's soul, enabling him to live on even if his body perished. That fragment had to be destroyed and if they somehow succeeded in finding all the objects Voldemort had used to keep his soul locked away, they would be able to eventually get rid of him too.

He had to tell about the Horcruxes to Dumbledore as soon as possible.

He discussed the matter with Remus, Eleanor, and Esmeralda, the three people close to him. Remus too agreed that Dumbledore should know about it and so it was decided to discreetly send a message to the headmaster of Hogwarts.

Dumbledore received the message and from then onwards, the Order changed their approach in dealing with the Dark Lord. They couldn't take him down in battle as his forces were expanding and they were all forced to go into hiding.

But they could search for those Horcruxes instead and get rid of them.

As Regulus had the Slytherin Locket in his possession, it was his responsibility to destroy that Horcrux and initiate the Order's mission to destroy the remaining Horcruxes as well.

He had read in the last surviving copy of the Secrets of The Darkest Art that there weren't many ways to destroy a Horcrux. It could only be destroyed by extremely powerful magic or a magical creature's venom.

He knew that cursed fire created using the spell Fiendfyre could destroy the Horcrux but it was very unstable magic and difficult to control. Regulus alone wouldn't be able to do it despite being a master of that curse.

So Remus offered to help him out and the two left for the forest one dark night to get rid of the Horcrux once and for all.

Eleanor and Esmeralda had been very anxious for them but they had strictly asked them to stay at home and not follow them. The lesser people there were around, the safer it would be to get that task done.

Plus, neither Regulus nor Remus wanted Elle and Esme to get hurt.

So the two wizards set off for the forest with the Slytherin Locket and were determined to destroy the Horcrux no matter what happened. They couldn't fail in that task regardless of the consequences.

They reached a clearing far from any human settlement so that their act of destruction wouldn't hurt anyone else. Remus exchanged a glance with him and he nodded, taking off the Locket and throwing it on the ground in front of him. 

Remus made a protective circle around Regulus, intending to shield him from the effects of the cursed fire. Regulus would be the one casting the spell for the cursed fire and Remus would at the same time keep the shield over him to protect him from getting burnt.

"Be careful," Remus warned him as he stepped back, knowing he too would get hurt if he stayed in close proximity.

Regulus inhaled deeply, trying to steady his racing heart, knowing the perilous task he was about to undertake. 

"This ends tonight," he whispered, eyeing the ominous emerald locket.

He stepped forward, and the locket seemed to pulse with an eerie green light as it slid off into the distance, sensing the threat that approached. Regulus raised his wand to cast the incantation for the cursed fire. Before he could cast the spell, dark tendrils shot out from its chain, attempting to ensnare him, but Regulus deftly sidestepped, narrowly avoiding the attack.

The air around him started to get thick and suffocating, dark fumes engulfing him. He could no longer see Remus on the other side as the smoke clouded him fully. He knew the Horcrux would fight back, it was after all a fragment of the Dark Lord's soul thus it was just as dark as its owner.

Regulus mustered all his courage and strength, casting protective spells to shield himself from the malevolent power while inching closer to the Horcrux.

With every step, the clearing in the forest seemed to grow darker, as if the locket itself fed off the fear and desperation of those who dare to approach it. But Regulus pressed on, his resolve unwavering. As he drew near, he could feel the locket's malefic presence clawing at his mind, trying to break his will.

Dark pictures began to form in front of him as the piece of soul in the Locket was trying to trick him. Images of Eleanor getting hurt, of him getting killed by Voldemort, and all the things he did not want to happen to them flashed in front of him.

he knew he couldn't give up, he had to stay strong. He would cast the spell despite everything the Horcrux tried to resist him.

"Fiendfyre!"

Regulus' wand glowed with a fierce red light as he focused his magic on the locket. The cursed fire erupted from the tip of his wand, ensnaring the locket in a blaze.

The fragment of Voledemort's soul with the locket let out a terrible screech, writhing in agony as it attempted to resist its destruction. But Regulus held steadfast, pouring every ounce of his strength into the spell.

The locket's defenses weakened, its malevolence diminishing as the fire chipped away at its enchanted protections. Regulus gritted his teeth, a sheen of sweat forming on his brow, as he concentrated with unwavering determination.

Finally, a piercing shriek escaped the locket, the fragment of Voldmort's soul trying one last attempt to fight its fate, but it was futile. In an explosion of orange light, the Slytherin locket shatters into countless pieces, leaving only ashes and a sense of profound relief in its wake.

Remus rushed forward to put out the fire, focusing a torrent of water to engulf the flames before the forest could be set ablaze.

Regulus collapsed to his knees, emotionally and physically drained from the harrowing encounter. But a sense of accomplishment filled him, knowing that he had taken a crucial step in dismantling Voldemort's reign of terror.

Remus came to support him and heaved him off the ground, asking if he was alright. He nodded, feeling exhausted as he leaned against Rem but at the same time, the knowledge of there being one less Horcrux to get rid of felt rewarding.

As Regulus gathered the remains of the destroyed Horcrux, he felt a strange mix of hope and trepidation. The fight against darkness was far from over, but he was willing to sacrifice everything to see it through.

***